Wheelchairs are well known transportation appliances enabling the infirm, disabled and unwell person to move about with greater mobility than otherwise. Essentially, wheelchairs are small, single person conveyances typified by a chair supported by two outer, large diameter drive wheels, and with two smaller pilot wheels or caster wheels located in front of the user's center of gravity. The chair may include a padded seat, or it may include a webbing or sling seat. Alternatively, the chair may be molded from a suitable material. A chair back is typically provided for the user's comfort. A leg rest assembly may be attached to the seat. Motive power may be supplied by an attendant pushing the wheelchair, by the user's hands and arms, or by an auxiliary power source.
While current designs of wheelchairs have proliferated, needs continue to arise that are not satisfactorily addressed by these current designs. For example, in current designs, it is often difficult to remove the leg support device for storage during travel or to adjust the leg support device for accommodation of single or double amputees. Such designs also often fail to provide a leg rest that is easily adjustable to support a particular leg length or that is adjustable to improve the space constraints when entering and exiting the wheelchair.
Other problems have arisen with regard to seating systems of current wheelchair designs. For example, present wheelchair seating systems are not always sufficiently collapsible into an easily stored configuration. Nor are present seat system designs easily adjustable to orient the height or center of gravity of the user when situated in the chair.
When a particular wheel camber is desired for a particular application, present designs often fail to provide a wheelchair wherein the wheel camber angle can be easily and quickly adjustable. Furthermore, in those designs that do have a variable camber feature, oftentimes, the wheel base and the seat height are undesirably affected after a camber angle change so as to result in a wheelchair being too wide or sitting too low.
Current designs also tend to have too rigid a framework. Consequently, travel over rough and unpaved surfaces can be especially uncomfortable to the user since shock and vibration is easily transmitted through the rigid framework.
When traveling, a user desires a wheelchair that is maneuverable through narrow passageways and that is convenient to store in a storage compartment, e.g., an aircraft storage bin. In addition, the especially active user prefers a wheelchair that is easily adaptable to different uses, e.g. for sports activities such as tennis or basketball or for normal transportation needs. Furthermore, a user prefers a wheelchair that is adjustable in a wide variety of positions so as to allow proper support according to the particular needs of a user. Current designs have not satisfactorily addressed all of these needs in a single wheelchair.
A general object of the invention is to provide a modular wheelchair that overcomes the limitations and drawbacks of the current designs, some of which have been described above.
Another object of the present invention is to provide a wheelchair having wide adjustability so as to provide proper support for a wide range of users under a wide range of uses.
Another object of the present invention is to provide a wheelchair that is Sturdy yet comfortable for a user during travel over a wide range of travel surface conditions.
Another object of the present invention is to provide a wheelchair that is easily maneuverable in cramped locations.
Another object of the present invention is to provide a wheelchair that allows ease of access by the user to and from the wheelchair.
Another object of the present invention is to provide a wheelchair that protects a user's clothing, hands, etc. from being damaged or injured during travel or braking of the wheelchair.
Another object of the present invention is to provide a wheelchair that is easily disassembled and assembled during travel or during adjustment of the wheelchair.
Another object of the present invention is to provide a wheelchair that is highly versatile yet economic to produce.
These and other objects not specifically enumerated above are accomplished by a modular wheelchair in accordance with the present invention.
The modular wheelchair in accordance with the present invention includes a main frame and a pair of main driving wheels. The main driving wheels are mounted on opposite sides of the main frame such that the main frame is positioned at a desired distance from the travel surface. A pair of casters are also mounted on opposite sides of the main frame, however, the pair of casters are situated forward of the pair of main driving wheels.
The modular wheelchair also includes a hub mechanism for adjusting a camber angle of each of the main driving wheels while maintaining the main frame at the desired distance from the travel surface.
A seat assembly is provided that is detachably securable to the main frame. The seat assembly includes a mechanism for adjusting the center of gravity of the seat assembly relative to the main frame while maintaining the main drive wheels at a predetermined wheel base.
These and other objects, advantages, aspects and features of the present invention will be more fully understood and appreciated by those skilled in the art upon consideration of the following detailed description of a preferred embodiment, presented in conjunction with the accompanying drawings.